I have had issues with the elevation readings all summer long. I consistently am missing at least 50%(and usually more) of my total elevation gain while cycling or mountain biking. I usually end up enabling the Elevation Correction. I have been in contact with support. On the first call, they told me to upgrade to the beta software and clean the sensor. I did both, and it still read erroneously. On the next call, I was instructed to default it back to factory settings and try again. After doing this, repairing all my sensors, etc, the elevation gain was still off by at least 50%. On the next call, they agreed to replace it under warranty. I recieved the new device, set it up, and it is doing the EXACT SAME THING. I now believe there is a software bug with 9.20. Does anyone else experience this? I can't believe I am the only one who has this issue, on 2 completely separate devices. Anyone from Garmin Support on here that can address this? This is a 600 dollar device and I believe it should work correctly. I hate having to use the USGS tables for elevation as they are highly inaccurate when mountain biking.
Please do not forget to contact Garmin on your issues. The forum is not a official issue tracking system from Garmin's perspective. Do also email garmin, this does get tracked and registered. The more official known issues the higher the issue wil get on the dev list.